Power transmission system for vehicle and vehicle comprising the same

A power transmission system for a vehicle, comprising:

• an engine unit configured to generate power;
• a transmission unit;
• a first motor generator coupled with the transmission unit;
• an output unit configured to transmit the power output by the transmission unit to at least one of front and rear wheels of the vehicle;
• and
• a synchronizer interposed between the transmission unit and the output unit,
• wherein the transmission unit comprises:
• a transmission power input part comprising a plurality of input shafts coaxially fitted over one another sequentially and a plurality of driving gears disposed on the plurality of input shafts, wherein the engine unit is configured to selectively engage with one of the plurality of input shafts to transmit the power to the one of the plurality of input shafts;
• and
• a transmission power output part comprising an output shaft and a plurality of driven gears disposed on the output shaft and configured to mesh with the plurality of driving gears on the plurality of input shafts, wherein the transmission power output part is configured to output the power from the transmission power input part to the output unit via the synchronizer interposed between the output unit and the output shaft of the transmission unit, wherein the synchronizer is connected to and in contact with the output shaft of the transmission unit,
• wherein the synchronizer is configured to synchronize a rotating speed of the output unit with a rotating speed of the output shaft of the transmission unit;
• and
• wherein the first motor generator is configured to adjust the rotating speed of the output shaft of the transmission unit according to the rotating speed of the output unit.